Answer: The shadow of the tree is 280 feet long.
Step-by-step explanation:
We can use a ratio to solve this:
Use the Height to shadow for each. This works because the fractions must reduce to the same equivalent.
5/10 = 140/x
We can see that 5/10 is 1/2, so we need another fraction using 140 as the numerator that is equal to 1/2. That's easy here: Multiply 140 × 2 to get the new denominator, 280 that replaces x. That is the length of the shadow.
If you have a less obvious ratio, you can use Cross Multiplication to solve the unknown value in the ratio:
5/10 = 140/x Cross multiply the numerator of the left side times the denominator on the right side, and the denominator on the left side by the numerator on the right side:
5 × x = 10 × 140
5x = 1400 Divide both sides by 5 (the 5s "cancel" on the left)
5x/5 = 1400/5
x = 280
I hope this helps, especially when you see more questions like this in the future.
